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Aim: Alien species successfully colonize new ranges if they encounter favourable environmental conditions there and possess traits that match new challenges. Climate‐matching approaches comparing native and exotic ranges mostly consider temperature and precipitation niches of alien species, but have largely ignored UV‐B radiation. UV‐B fundamentally differs between hemispheres, with much higher levels at southern than at northern latitudes. Consequently, UV‐B might act at the global scale and present a so far neglected filter that species need to overcome when invading high‐UV‐B environments. Location: We performed two multi‐species common garden experiments, conducted in the native European range (Germany) and the high‐UV‐B exotic range (New Zealand) to test for preadaptation to UV‐B. Methods: We used 25 herbaceous species from open habitats, which we exposed in each range to three UV radiation treatments: (a) natural sunlight, (b) exclusion of UV‐B while allowing natural UV‐A, and (c) exclusion of UV‐B and UV‐A. We additionally used plant traits (TRY), global distribution data (GBIF, GloNAF) and global UV‐B satellite data (glUV) to determine species‐specific characteristics as fostering agents of UV‐B tolerance. The joint analysis of experimental and macroecological data allowed quantification of species plasticity and identification of beneficial species traits in high‐UV‐B environments. Results: Our results showed an overall limiting effect of UV‐B in both common gardens but the UV‐stress response tended to be more pronounced in the invaded range. Across all species, we found little evidence for preadaptation by functional plant traits. In contrast, preadaptation to climatic conditions related to the species' native UV‐B niche was of greater importance for plant performance in the presence of UV‐B radiation. Main conclusions: For predicting alien species' ability to expand into high‐UV‐B environments, macroclimatic niche characteristics of the species' native range might be better predictors than functional traits and should be more considered in future projection models. [ABSTRACT FROM AUTHOR]

Aim: The loss of biodiversity has raised serious concerns about the entailing losses of ecosystem services. Here, we explore the potential of repeated habitat mapping data to identify floristic changes over time. Using one German federal state as a case study, we assessed floristic changes between the 1980s and 2010s. These habitat data have great potential for analysis because of their high spatial coverage while also posing methodological challenges such as incomplete observation data. We developed a modelling approach that accounts for incomplete observations and explored the ability to detect temporal trends. Location: The Federal State of Schleswig‐Holstein (Germany) Methods: We compiled plant species lists from the earliest (1980s) and most recent (2010s) habitat mapping survey and aligned differing habitat definitions across mapping campaigns. A total of 5,503 mapped polygons, each with a list of species records, intersected the two surveys. We accounted for underrecorded species by assigning occurrence probabilities, based on species co‐occurrence information across all surveys, using Beals' index and tested the robustness of this approach by simulation experiments. For those species with significant increases and decreases in occurrence probability, we linked these trends to the species' functional characteristics. Results: We found a systematic loss of species that are moderately threatened. Species that indicate low nitrogen supply and high soil moisture declined, suggesting a shift towards a more eutrophic and drier landscape. Importantly, assessing specific plant traits associated with losses, we also detected a decrease in species with reddish and blueish flowers and species providing nectar, pointing to a decrease of insect‐pollinated taxa. Main conclusions: The identified changes raise concerns that plant biodiversity has fundamentally changed over the last three decades, with concomitant consequences for ecosystem services, especially pollination. Given the general lack of historical standardized data, our approach for trend analyses using incomplete observation data may be widely applicable to assess long‐term biodiversity change. [ABSTRACT FROM AUTHOR]